Mandrel for sheet-metal working.



L. O. SHARP.

MANDREL FOR SHEET METAL WORKING.

APPLICATION FILED MAR.8, 1907. RENEWED OUT. 2, 1911.

Patented May 7, 1912.

COLUMBIA PLANOGRAPM, uu., WASHINGTON, v4 :4

UNITED STATES PATENT OFFICE.

LEE 0. SHARP, OF PLATTSMOUTH, NEBRASKA, ASSIGNOR T0 FRANZ BRITCKMANN,JR., OF BRUNSWICK, GERMANY.

MAN'DREL FOR SHEET-METAL WORKING.

Specification of Letters Patent.

Patented May '7, 1912.

Application filed March 8, 1907, Serial No. 361,310. Renewed October 2,1911. Serial No. 652,414.

To all whom it may concern:

Be it known that I, LEE C. SHARP, of the city of Plattsmouth, in thecounty of Cass and State of Nebraska, have invented certain new anduseful Improvements in Mandrels for Sheet-Metal orking, of which thefollowing is a full, clear, and exact specification, such as will enableothers skilled in the art to which it appertains to make and use thesame.

My invention relates particularly to a mandrel for forming and holdingcan body blanks in position for seaming them.

It is especially adapted to the formation of lap seams, that is to say,in which one edge of the blank is lapped over the other to form the seamwhich is subsequently soldered to render it permanent. Heretoforedevices of this sort have been composed of a horn or mandrel aroundwhich the blank tin is folded and held by wings or other devicesengaging the tin.

The object of my invention is to dispense with these devices forengaging the tin to hold it on the horn.

A further object of my invention is to provide means for holding the lapparts of the body at the seam firmly together so that the engagement ofthe edges during the soldering operation will not depend upon thepressure of the soldering tool, thus enabling me to join together thetwo edges of the body blank and secure them by the fusing of the tinwith which the metal plate is coated.

I attain these objects by magnetic action which may be through themandrel itself, or a part in connection therewith. The magnet ispreferably of the electromagnetic type, although my invention is not solimited.

My invention involves various other features of major or minorimportance, and all will be fully set forth hereinafter and particularlydescribed in the claims.

Reference is had to the accompanying drawings which illustrate, asexamples various types of the invention, in which drawin s Tigure 1 is asectional view of one form of the mandrel; Fig. 2 is a sectional view ofa second form; and Fig. 3 is a sectional View of a third form.

In Fig. 1, the mandrel is composed of two approximately semi-cylindricalsections a which form the poles of the magnet and are joined by a magnetcore 6 around whichthe winding 0 is placed. The can body blank indicatedat (Z is folded either manually or by machinery over the mandrel orhorn, and its edges lapped as indicated at d to form the lap seam. Uponenergizing the coil 0 the blank will be attracted to the mandrel at thepoints indicated by the arrows in Fig. 1, and the magnetic force may bemade sufliciently great to hold the sheet metal plate in position asfirmly as will be desired under any condition. It will be observed thatthe force holding the blank is exerted from the interior of the mandrelas contradistinguished from the exterior thereof, thus leaving the outerside of the can body entirely free and unobstructed particularly at theseam, without, however, in any way affecting the force which may beexerted to hold the edges of the blank firmly lapped against each other.This allows the soldering operation to be carried on without restraintand when the can is to be removed from the mandrel the coil 0 may bedeenergized and the can withdrawn easily. In sealing the seam by fusingthe tin with which the metal plate is coated, my invention becomespeculiarly useful. It is a. fact that commercial tin plate composed ofsheet steel coated with tin furnishes sufficient tin to solder the lapseam. However, it has been heretofore impossible to solder the scam inthis manner owing to the fact that great pressure must be applied to theoverlapped parts during the fusing operation, otherwise the parts willwarp and the hermetic joint be prevented. By means of my magneticmandrel, however, the lapped parts of the seam are held firmly againsteach other by pressure which may be as great as necessary and theheating operation necessary to fuse the tin and form the joint may becarried on unrestrained. The magnetic force may be continued on the seamuntil the tin cools 100 and sets, and the seam is then complete.

Fig. 2 shows a modification in which the mandrel is adapted to beprovided with a number of longitudinally disposed windings of which oneis indicated at c. windings are arranged in all of the cavities aroundthe entire circumference of the mandrel with the result that uponenergization of the windings the blank cl is held firmly at all points.

Similar Fig. 3 shows a form which is rectangular in cross section,adapted for the formation of square cans in which the parts a, Z), and 0correspond to the parts a, b and c of Fig. 1, and perform precisely thesame functions.

It is also pointed out in connection With this invention that themandrel may be made of any length desired, thus enabling a can of anylength to be constructed and indeed adapting the invention. to theformation of various other tubular sheet metal articles of indefinitelength.

Having thus described the preferred embodiment of my invention, what Iclaim as new and desire to secure by Letters Patent of the United Statesis:-

1. A horn or mandrel adapted to support the blanks of sheet metal cansand having cross-sectional shape corresponding to that of the can, saidhorn or mandrel being provided with electromagnetic means acting uponthe inner surface of the blank to hold the blank in position around themandrel leaving the outer surface of the blank un obstructed.

2. A horn or mandrel adapted to have the blanks of sheet metal cansformed around it,

the horn or mandrel having a cross-sectional shape corresponding to thatof the can and an electromagnetic means embodied within the horn ormandrel as a part thereof, whereby said blank may be held around themandrel in position for soldering, leaving the outer part of the blankunobstructed during the soldering operation.

3. A horn o mandrel for forming the sheet metal cans comprising twosections forming the poles of a magnet and spaced from each other, saidsections forming to the cross-sectional shape of the can, a mag net corejoining the said sections together and an electric magnet Winding aroundthe core, whereby the blank of the sheet metal can is held around themandrel by electromagnetic force exerted from the interior thereof andthe outer portion of the blank is left unobstructed during the solderingoperation.

In testimony whereof I have hereto pu my hand this 15th day of February,1907.

LEE C. SHARP Witnesses IsAAo B. OWENS, ETHEL MOLAUGHLIN.

C(pies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, I). O.

